On Mon, Nov 17, 2008 at 9:03 AM, Prof Brian Ripley <[EMAIL PROTECTED]> wrote: > On Mon, 17 Nov 2008, hadley wickham wrote: > >> Hi all, >> >> I love the option to not automatically convert strings into factors, >> but there are three places that the current option doesn't work where >> I think it should: > > Perhaps you mean 'when I would like it to'? Things *should* work as > documented, surely?
In an ideal world, I think things should be documented *and* consistent. >> options(stringsAsFactors = FALSE) >> >> str(expand.grid(letters)) >> str(type.convert(letters)) >> >> df <- read.fwf(textConnection(paste(letters,collapse="\n")), 1) >> str(df) > > I get > >> str(df) > > 'data.frame': 26 obs. of 1 variable: > $ V1: chr "a" "b" "c" "d" ... > > so what is wrong with that? read.fwf just calls read.table, so the default > options of read.table apply. Ok, that's weird. I get factors. >> I think type.convert and read.fwf can be fixed by giving them a >> stringsAsFactors argument and then using asis = !stringsAsFactors >> (like read.table). > > Seems to me that there is nothing wrong with read.fwf. For type.convert() > we could have the default > > as.is = !default.stringsAsFactors() > > but I think a strong case needs to be made to change the documented > behaviour. Well, my intuition was that type.convert should mirror the behaviour of read.table, since it is what does the conversion behind the scenes. I can of course change my own code. >> The key lines in expand.grid would seem to be >> >> if (!is.factor(x) && is.character(x)) >> x <- factor(x, levels = unique(x)) >> >> but I'm not sure why they are being converted to factors in the first >> place. > > Nor I am, but it goes back to at least r2107, over 10 years ago. I don't > see much problem with adding a 'stringsAsFactors' argument there. Great, thanks. Hadley -- http://had.co.nz/ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
